first review doc

8/12/2019 First Review Doc

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CAN BASED WIND TURBINE WITH ONLINE

MONITORING AND CONTROLLING

A PROJECT REPORT

Submitted by

AJAY M (31610106002)

JEYAVIJAY N (31610106041)

AZARUDEEN A (31610106303)

EC241 ! PROJECT WOR"

ELECTRONICS AND COMMUNICATION DEPARTMENT

AGNI COLLEGE O# TECHNOLOGY$ THALAMBUR

ANNA UNIVERSITY% CHENNAI 600 02

APRIL$ 2014


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AGNI COLLEGE OF

TECHNOLOGY

Affiliated to Anna University, Chennai.Approved by AICTE & Accredited by NBA, New Delhi. ISO 9001:2008 Certified Institution.

BNA!IDE CE"TI!ICATE

Certified that this is Bonafide "ecord of #ractical $or% done by

. A'A( ) *++

-. 'E(AI'A( N *++/

*. A0A"UDEEN A *++**

of B.E. 1th se2ester 3Electronics and Co224nication

En5ineerin56 in the #"'ECT $"7 3EC-/86 d4rin5 the year

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:ead of the Depart2ent ;taff9in9

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Su!itted for t"e #r$%ti%$& E'$!in$tions "e&d on ((((((.


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INTE)NAL E*A+INE) E*TE)NAL

E*A+INE)

TABLE O# CONTENTS

CHAPTER TITLE PAGE NO&

1) INTRODUCTION

2) BAC"GROUND

3) #AULT DIAGNOSIS AND

#AULT TOLERANT CONTROL

4) E'ISTING #AULT DIAGNOSIS

AND #AULT TOLERANT

CONTROL METHODS

) #AULT DIAGNOSIS AND

#AULT TOLERANT CONTROL O#WIND TURBINES

6) CAN (CONTROLLED AREA

NETWOR")

) CAN IN WIND TURBINE

) TRANSISTORS


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INTRODUCTION% In this chapter the background and motivation for the need of fault

diagnosis and fault-tolerant control of wind turbines are described.

A brief overview of fault diagnosis and fault-tolerant control and

the application to wind turbines is then given.

This is followed by presenting the scope of the project and

outlining the content of the this.

BAC"GROUND%Evolution of technology has increased power demands to

operate the modern electrical euipment.

This has increased the demand for fossil fuels and has made

electrical energy more e!pensive.

"ecause of such high demands for electric power# it is

necessary to focus on renewable energy sources# as fossil fuelresources are limited. $urthermore# to protect the

environment the emissions of greenhouse gases and undesired

particles into the atmosphere have to be reduced.

Among the renewable energy sources available today# wind

power is the world%s fastest growing &'ind Energy (ews#

)**+,. 'ith an annual growth rate in installed wind energy

capacity of * on average throughout the past /* years#wind turbines are de0nitely up and coming &1'E2# )**3#p.

/4,. $or several reasons wind energy is growing fast5 it is

cheap# ine!haustible# widely distributed#clean# and climate

friendly &'ind Energy (ews# )**+,.

As many wind turbines are installed o0shore# a non-planned

service can be highly costly# so it would be bene0cial if fault-


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tolerant control schemes could help the turbines produce

some energy from the time a fault is detected to the ne!t

planned service. $urthermore# the implementation of fault

diagnosis schemes entails operational bene0ts due to its

feature of early detection of faults# which can make the windturbine operate safer and reduce costs as a result of possible

improved maintenance procedures &6ameed et al.# )**3# p.

,.

Therefore# fault diagnosis and fault-tolerant control of wind

turbines may over several benefits.

7revent catastrophic failures and faults deteriorating other parts

of the wind turbine by early fault detection andaccommodation.

8educe maintenance costs by avoiding replacement of

functional parts# by applying condition based maintenance

instead of time-based maintenance.

7rovide diagnostic details to the maintenance the state by

remote diagnosis.

Increase energy production when a fault has occurred by means

of fault-tolerant control.

This section has addressed benefits of e!ploiting wind power

and improving the reliability of

#AULT DIAGNOSIS AND #AULT TOLERENT CONTROL%

The purpose of this section is to give an introduction to fault

diagnosis and fault-tolerant control#since these topics are addressed

in this thesis. This is accomplished by providing a brief overviewof

the terminology and available methods in these fields.$inally# the

available fault diagnosis a fault-tolerant control algorithms for wind

turbines are discussed.


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$ault-tolerant control system is a system# which prevents component

failures from becoming

failures on the system level. The control system is though allowed to

have degraded performance

in some cases when e!posed to a fault. A fault is a change in thecharacteristics of a component#

while a failure makes a component completely dysfunctional. 9verall#

there are two di0erent types of fault-tolerant control systems: these

are called passive fault-tolerant control systems ;7$T2S< and active

fault-tolerant control systems ;A$T2S< &=hang and >iang# )**,.

7assive fault-tolerant control systems are designed to be resilient to a

speci0ed set of faults.This implies that the same controller is utili?ed

both for the fault-free as well as the faulty system.In the design of

passive fault-tolerant control systems# di0erent performancereuirements are set

up for the normal system and for the faulty system &(iemann and

Stoustrup# )**4b,.Therefore#these systems are not referred to as

robust systems# but as reliable systems.

Active fault-tolerant control systems have# in contrast to passive fault-

tolerant control

systems# different controllers for the normal system and for the faulty

system. This implies that the state of the system has to be determined

by fault diagnosis algorithms. The information from the fault

diagnosis algorithms is utili?ed in a supervisor# to reconfigure the

control system for

accommodating faults.$ault diagnosis used in active fault-tolerant

control systems consists of multiple parts# since faults both have to be

detected# isolated# and in some cases estimated. $ault detection should

detect that a fault has occurred and can rely on either an active or a

passive approach. 7assive fault detection should detect faults by

comparing the e!pected system behavior with the observed system

behavior: hence# it does not a0ect the system. In contrast to this#

active fault detection uses injection of au!iliary signals into a systemto improve the fault detection capabilities or in some cases make fault

detection possible.$ault isolation should point out faulty components

in

the system. This is important information when faults should be

accommodated# since the control system cannot rely on a faulty

component. Some faults do not turn a component on or off# but have

an intermediate state. This implies that fault estimation has to

determine the fault si?es in order to accommodate these.

There are generally two types of faults5 abrupt faults and incipientfaults. An abrupt fault


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is generally easier to detect than an incipient fault# but it might have

severe conseuences for the system# since it happens instantaneously.

E'ISTING #AULT DIAGNOSIS AND #AULT TOLERENT

CONTROL METHODS%

There e!ists several methods for designing fault diagnosis algorithms

and fault-tolerant controllers# and the basics of these are outlined in

this subsection.In the design of a passive fault-tolerant control system

a good performance for the nominal control system has to be achieved

while a graceful degradation is allowed in the case of a fault. In

&(iemann and Stoustrup# )**4b, this is achieved by creating acontroller structure relying on two separate controllers. 9ne controller

outputs nothing when the control system possesses nominal behavior#

while the second controller euals the nominal controller. In the case

of a fault# the fiest controller outputs a non-?ero value: hence#

changing the behavior of the control system. 9ther methods# as e.g.

&@iao et al.# )**,# rely on a multi-objective control system# which

has a set of minimum reuirements to the faulty system and are

optimi?ed to improve the performance of the

normal system. In the design of an active fault-tolerant control systemthe first step is to design a fault diagnosis system. This essentially

consists of designing a residual generator which is sensitive towards

faults and insensitive towards other e!ogenous inputs to the system.

ethods for this include parity space approaches where# if possible# a

perfect decoupling between disturbances and residual is

designed.Another approach is to design a change detection algorithm#

e.g. based on a 2BSB test# which

is able to detect a change in the mean value of a signal.

$inally# Calman filter approaches can be

utili?ed by making a description of the fault become part of the

system model# allowing the fault to be estimated. These approaches

are suitable for diagnosing incipient faults.

'hen the fault has been diagnosed the active fault-tolerant control

system must be reconfigured.This could for e!ample be to reconfigure

the controller to rely on estimates instead of measurements.The active

fault-tolerant control system is recon0gured by use of a supervisor#

which chooses an appropriate controller from a family of possible

controllers# designed for each fault state.


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#+,-. D/+/ + #+,-.5T-7+. C.7- 8 W/ T,79/%

In this subsection the current state of fault diagnosis and fault-tolerant

control of wind turbines is outlined# by e!amining the available

literature.odern wind turbine control systems are euipped withcondition monitoring systems and fault detection systems. These systems

detect and isolate faults and determine the current operating conditions

of the wind turbine. The available information can then be utili?ed for

predictive maintenance#which basically predicts when maintenance

should be performed to avoid failures.ost condition monitoring

systems and fault detection systems in wind turbines are signalbased and

utili?e e.g. vibration analysis to detect and isolate faults. This has

enabled successful condition monitoring of bearings in the gearbo! and

the generator among others. (umerous other signal-based approachesutili?ed in wind turbines can be found in &6ameed et al.# )**3,.9nly a

few model-based fault diagnosis approaches e!ist for wind turbines:

among these are fault diagnosis systems for pitch sensors and pitch

actuators &'ei and Derhaegen# )**, and &Fonders#)**),. These

diagnosis systems estimate some parameters in the pitch system# and

determine if a fault has occurred based on these estimates.

It has not been possible to find any fault-tolerant control systems for

wind turbines in the literature

review. The common approach is to deploy condition monitoring

systems and shut down the

wind turbine in case of a fault. 6owever# in a few cases thoughts about

fault accommodation have

been presented# but have not been tested or simulated.In this section the

terminology and available methods used in the fields of fault diagnosis

and fault-tolerant control have been outlined. Additionally# fault

diagnosis and fault-tolerant control applied to wind turbines have been

investigated.The investigation has revealed that fault diagnosis

algorithms e!ist for wind turbines# but mostly using signal-based

methods. Additionally# only a few fault-tolerant control systems for windturbines have been found.

CAN(CONTROLLER AREA NETWOR")%

This paper presents a methodology to provide an +:+;

+,.


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offer increase portability and efficiency compare with other possible

protocols for car automation. The benefits of 2A( in achieving

automation# over other tradition schemes will offer increase fle!ibility

and e!pandability for future technology.

CAN IN WIND TURBINE%

This paper is a 2A( based architecture designed for the purpose of

monitoring and fault diagnosis of wind turbine.

2A( is a essage based protocol designed specifically for

Automotive# later Aerospace# Industrial automation and edicaleuipmentGs.

2A( interface module is used to communicate the monitored

parameters between the wind turbine and the control center.

Furing the transmission of the data from one node to another node

disturbance occurs. To avoid these disturbances we propose 2A(

protocol.

T7+/.7%

#,;./

Transistors + ;,77.# for e!ample they

can be used to amplify the small output current from a logic chip so

that it can operate a lamp# relay or other high current device.

In many circuits a resistor is used to convert the changing current to a

changing voltage# so the transistor is being used to + :-.+.

A transistor may be used as a ?/.;@;either fully on with ma!imum

current# or fully off with no current< and as an +


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T>= 8 .7+/.7%

There are two types of standard transistors# NPN and PNP# with

different circuit symbols. The letters refer to the layers of

semiconductor material used to make the transistor.

ost transistors used today are (7( because this is the easiest type

to make from silicon.

If you are new to electronics it is best to start by learning how to use

(7( transistors.

The leads are labelled 9+;"


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ARM (LPC214)%

The (7 ;founded by 7hilips< @72)/J is an A8+TFI-S based

high-performance )-bit 8IS2 icrocontroller with Thumb

e!tensions 4/)C" on-chip $lash 89 with In-System 7rogramming

;IS7< and In-Application 7rogramming ;IA7


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MODELLING%

To facilitate a model-based approach in the design of the fault

diagnosis and fault-tolerant control

algorithms# a non-linear model of a variable-speed# variable-pitch

wind turbine is set up. Additionally#

the model acts as a simulation model for testing the designed

algorithms. The model is based on a static model of the aerodynamics#

a two-mass model of the drive train# an electromechanical model of

the generator# dynamic actuator models# and ?ero-mean 1aussian

distributed measurement noises. The parameters for the wind turbine

model are provided by kkelectronic aKs# similar applies for the

variances of the additive measurement noises. The input to the model

is generated by a wind model# which includes wind shear# tower

shadow# and turbulence.The aerodynamics of the wind turbine is non-linear and is

described in form of a lookup table# where the e0ciency of the

aerodynamics is determined from the pitch angles of the blades and

the tip-speed ratio. This part of the model is non-linear and introduces

parameters that vary dependent on the operating conditions.

#AULT ANALYSIS%A fault analysis is performed in order to determine the faults which

should be considered in this project. $irst# a number of possiblecomponent faults are chosen and their propagations through the

system are determined by describing their effects on the surrounding

components of the system.Subseuently# the severity of the end-

e0ects and the occurrence rates of the faults are estimated to select the

faults of highest priority.The freuency of the faults are appro!imated

based on statistics reported in the literature#whereas the severities of

their end-e0ects are determined based on simulations. $or conducting

these simulations# a reference controller without fault-tolerant

capabilities is designed based on information about an e!istingcontrol system. To limit the number of faults to be handled during this

project# it is decided to focus on the faults related to the pitch sensors#

pitch actuators# and generator speed sensor.

The motivation behind selecting faults related to the pitch system#

which e.g. cause rotor unbalance#is that these faults increase fatigue

loads on the wind turbine structure. It is further seen that changed

dynamics of the pitch system# caused by low pressure or high air

content in the hydraulic oil# may result in an unstable closed-loopsystem. $inally# the main controllers in the entire operating range of


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the wind turbine depend solely on the measured generator speed.

6ence# it is

essential to diagnose and accommodate any troubles regarding this

particular measurement.

#AULT 5TOLERANT CONTROL%

In the design of the fault-tolerant control system the faults are divided

into two categories5 faults that do not a0ect the dynamics of the

system and faults that a0ect the dynamics of the system.The faults

that do not affect the dynamics of the system are accommodated by

correcting the measurement and reference signals# based on

information provided by the fault diagnosis algorithms.This enables

the fault-tolerant control system to be designed independent of the

controller structure and without affecting the nominal performance ofthe control system.$aults that affect the dynamics of the system are

accommodated using both active and passive fault-tolerant control# to

enable a comparison of the two methods. The main difference

between these methods is that the active fault-tolerant controller

depends on the fault diagnosis algorithms#while the passive fault-

tolerant controller is independent of these algorithms. "oth fault-

tolerant

controllers are @7D controllers# which are based on a common @7D

system description# accounting for the parameter-varying nature of thewind turbine.

CONCLUSION%

In this project fault diagnosis and fault-tolerant control algorithms are

developed for improving the reliability of wind turbines. The study is

based on a model of a variable-speed# variablepitch J5 ' wind

turbine# which represents a realistic but 0ctitious wind turbine# towhich the collaborator kk-electronic aKs has provided the parameters.

The faults considered in the project are chosen based on a severity

and occurrence analysis# in which the most freuent and severe faults

are identified. The analysis primarily focuses on sensor and actuator

faults# which are included in

the model of the wind turbine.

In the diagnosis of the faults# model-based fault diagnosis

algorithms are primarily developed#


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due to their improved resilience towards making incorrect decisions

compared to signal-based approaches.Additionally# only the already

available sensor information is utili?ed in the diagnosis of

the faults. To obtain a fault-tolerant control system# di0erent

approaches are utili?ed dependenton the nature of the faults. $or faults that affect the dynamics of the

system# active and passive

fault-tolerant controllers are designed and compared.

To access the performance of the designed algorithms# onte 2arlo

simulations are performed to evaluate the robustness of the

algorithms# where this is considered necessary.

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